<h4>Tool</h4><table border="0"><tr><td valign="top"><b>Name</b></td><td valign="top">Analytical Hillshading</td></tr><tr><td valign="top"><b>ID</b></td><td valign="top">0</td></tr><tr><td valign="top"><b>Author</b></td><td valign="top">O.Conrad, V.Wichmann (c) 2003-2013</td></tr><tr><td valign="top"><b>Specification</b></td><td valign="top">grid</td></tr></table><hr><h4>Description</h4>Analytical hillshading calculation.
Method 'Ambient Occlusion' is based on concepts of Tarini et al. (2006), but only the northern half-space is considered.

References:
Tarini, M. / Cignoni, P. / Montani, C. (2006): Ambient Occlusion and Edge Cueing to Enhance Real Time Molecular Visualization. IEEE Transactions on Visualization and Computer Graphics, Vol. 12, No. 5, pp. 1237-1244.
<hr><h4>Parameters</h4><table border="1" width="100%" valign="top" cellpadding="5" rules="all"><tr><th>Name</th><th>Type</th><th>Identifier</th><th>Description</th><th>Constraints</th></tr>
<tr><th colspan="5">Input</th></tr><tr><td>Elevation </td><td>Grid (input)</td><td>ELEVATION</td><td></td><td></td></tr><tr><th colspan="5">Output</th></tr><tr><td>Analytical Hillshading</td><td>Grid (output)</td><td>SHADE</td><td>The angle between the surface and the incoming light beams, measured in radians.</td><td></td></tr><tr><th colspan="5">Options</th></tr><tr><td>Shading Method</td><td>Choice</td><td>METHOD</td><td></td><td>Available Choices:
[0] Standard
[1] Standard (max. 90Degree)
[2] Combined Shading
[3] Ray Tracing
[4] Ambient Occlusion
Default: 0</td></tr><tr><td>Azimuth</td><td>Floating point</td><td>AZIMUTH</td><td>Direction of the light source, measured in degree clockwise from the North direction.</td><td>Minimum: 0.000000
Maximum: 360.000000
Default: 315.000000</td></tr><tr><td>Height</td><td>Floating point</td><td>DECLINATION</td><td>Height of the light source, measured in degree above the horizon.</td><td>Minimum: 0.000000
Maximum: 90.000000
Default: 45.000000</td></tr><tr><td>Exaggeration</td><td>Floating point</td><td>EXAGGERATION</td><td>The terrain exaggeration factor allows one to increase the shading contrasts in flat areas.</td><td>Default: 4.000000</td></tr><tr><td>Shadow</td><td>Choice</td><td>SHADOW</td><td>Choose 'slim' to trace grid node's shadow, 'fat' to trace the whole cell's shadow. The first is slightly faster but might show some artifacts.</td><td>Available Choices:
[0] slim
[1] fat
Default: 1</td></tr><tr><td>Number of Directions</td><td>Integer</td><td>NDIRS</td><td>Number of sample directions for ambient occlusion. Divides azimuth range (270 to 0 to 90 degree) into sectors. Declination (0 to 90 degree) is divided in (Number of Directions / 4) sectors.</td><td>Minimum: 2
Default: 8</td></tr><tr><td>Search Radius</td><td>Floating point</td><td>RADIUS</td><td>Radius used to trace for shadows (ambient occlusion) [map units].</td><td>Minimum: 0.001000
Default: 10.000000</td></tr></table>